IC ADC0804 – 8-Bit Analog-to-Digital Converter

Overview

The IC ADC0804 – 8-Bit Analog-to-Digital Converter is an 8-bit analog-to-digital converter (ADC) designed for converting analog signals into digital data. It is commonly used in applications where accurate digital representation of an analog signal is required, such as in data acquisition systems, sensors, and various digital instrumentation.

Features

• 8-Bit Resolution: Converts an analog input signal into an 8-bit digital output, providing 256 discrete levels.
• Parallel Output: Outputs data in a parallel format, making it easy to interface with digital systems and microcontrollers.
• Analog Input Range: Typically accepts an analog input range of 0 to 5V, which is suitable for many common signal levels.
• Single Supply Operation: Operates with a single +5V supply, simplifying the power requirements.
• Built-in Reference Voltage: Includes an internal reference voltage that can be used to set the analog input range.
• Low Power Consumption: Designed to operate with minimal power, making it suitable for battery-operated and low-power applications.

Pin Configuration

The ADC0804 is usually available in a 20-pin Dual In-line Package (DIP) with the following pin configuration:

• Pin 1: V_REF- – Negative reference voltage input (typically connected to ground).
• Pin 2: V_REF+ – Positive reference voltage input (typically connected to +5V).
• Pin 3: V_IN – Analog input signal.
• Pin 4: AGND – Analog ground.
• Pin 5: A0 – Address line 0 (for multiple ADCs).
• Pin 6: A1 – Address line 1 (for multiple ADCs).
• Pin 7: A2 – Address line 2 (for multiple ADCs).
• Pin 8: CS – Chip select (active low).
• Pin 9: RD – Read (active low).
• Pin 10: WR – Write (active low).
• Pin 11: D0 – Data output bit 0.
• Pin 12: D1 – Data output bit 1.
• Pin 13: D2 – Data output bit 2.
• Pin 14: D3 – Data output bit 3.
• Pin 15: D4 – Data output bit 4.
• Pin 16: D5 – Data output bit 5.
• Pin 17: D6 – Data output bit 6.
• Pin 18: D7 – Data output bit 7.
• Pin 19: V_CC – Supply voltage (+5V).
• Pin 20: DGND – Digital ground.

(Note: Pinout can vary slightly depending on the package type and manufacturer.)

Working Principle

1. Analog Input Sampling: The ADC0804 samples the analog input voltage applied to Pin 3 (V_IN). The analog signal is compared to an internal reference voltage.
2. Analog-to-Digital Conversion: The analog signal is converted into a digital representation using successive approximation. The result is an 8-bit binary number that corresponds to the input voltage level.
3. Output Data: The digital output is available in parallel format on pins D0 to D7. The data is read by a microcontroller or digital system using the RD (Read) signal.
4. Control Signals: The ADC0804 uses control signals (CS, RD, WR) to manage the conversion process and data retrieval. The chip select (CS) signal enables the ADC, while the read (RD) and write (WR) signals control the data transfer.

Applications

• Data Acquisition: Used in systems that require accurate measurement and digitization of analog signals, such as temperature sensors, pressure sensors, and light sensors.
• Microcontroller Interfacing: Interfaces with microcontrollers to convert analog inputs into digital data for further processing or control.
• Instrumentation: Provides digital outputs for various instrumentation and measurement systems.
• Signal Processing: Converts analog signals into digital form for digital signal processing applications.

Example Circuit

• Basic ADC Configuration: Connect the analog input signal to Pin 3 (V_IN). Provide the reference voltage to Pins 1 and 2 (V_REF- and V_REF+). The output data can be read from Pins 11 to 18 (D0 to D7) using the RD signal.

Advantages

• Easy Integration: Simple interface with parallel digital output, making it easy to connect to microcontrollers and digital systems.
• Low Power: Operates with low power consumption, suitable for battery-operated devices.
• Single Supply: Operates with a single +5V supply, simplifying the power supply design.

Conclusion

The ADC0804 is a versatile 8-bit analog-to-digital converter that provides accurate digital representation of analog signals. Its parallel output, low power consumption, and easy integration make it suitable for a wide range of applications in data acquisition, instrumentation, and microcontroller interfacing. Whether used for simple measurements or more complex signal processing tasks, the ADC0804 delivers reliable performance and ease of use.

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